In recent years, flat panel display devices that use flat panel display elements such as liquid crystal panels and plasma display panels are replacing cathode ray tube displays in display elements for image display devices such as television receivers, allowing image display devices to be made thinner. Liquid crystal panels used in liquid crystal display devices do not emit light on their own, and therefore, it is necessary to provide a separate backlight device as an illumination device. A known example of such a backlight device is an edge-lit type backlight device in which a light-receiving face is provided as a side face of a light guide plate, and a planar light source such as an LED is provided facing the side face of the light guide plate.
In some cases, edge-lit type backlight devices have support members that support (hold) the light source substrates on which the planar light sources are respectively disposed. This type of support member is disposed on a case such as the chassis. As a result, heat generated in the vicinity of the light source substrate can be effectively dissipated to the case through the support member, thereby realizing a backlight device having an excellent heat dissipating effect. Patent Document 1 discloses a display device including an edge-lit type planar light source device having this type of support member, for example.